/**
* 测量线段
*/
function MeasureTools(viewer) {
var entityCollection = [];
var handler=new Cesium.ScreenSpaceEventHandler(viewer.canvas);
this.getCollection = function () {
return entityCollection;
};
/**
* 清除
*/
this.destroy = function () {
for (var i = 0; i < entityCollection.length; i++) {
viewer.entities.remove(entityCollection[i]);
}
entityCollection = [];
};
/**
* 测距
*/
this.measurePolyLine = function () {
var positions = [];
var labelEntity = null; // 标签实体
// 注册鼠标左击事件
handler.setInputAction(function (clickEvent) {
var cartesian = viewer.scene.pickPosition(clickEvent.position); // 坐标
// 存储第一个点
if (positions.length == 0) {
positions.push(cartesian.clone());
addPoint(cartesian);
// 注册鼠标移动事件
handler.setInputAction(function (moveEvent) {
var movePosition = viewer.scene.pickPosition(moveEvent.endPosition); // 鼠标移动的点
if (positions.length == 2) {
positions.pop();
positions.push(movePosition);
// 绘制label
if (labelEntity) {
viewer.entities.remove(labelEntity);
entityCollection.splice(entityCollection.indexOf(labelEntity), 1);
}
// 计算中点
var centerPoint = Cesium.Cartesian3.midpoint(positions[0], positions[1], new Cesium.Cartesian3());
// 计算距离
var lengthText = "距离：" + getLengthText(positions[0], positions[1]);
console.log(lengthText)
labelEntity = addLabel(centerPoint, lengthText);
entityCollection.push(labelEntity);
} else {
positions.push(movePosition);
// 绘制线
addLine(positions);
}
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
} else {
// 存储第二个点
positions.pop();
positions.push(cartesian);
addPoint(cartesian);
handler.removeInputAction(Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.removeInputAction(Cesium.ScreenSpaceEventType.MOUSE_MOVE);
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
};
/**
* 测面积
*/
this.measurePolygon = function () {
var positions = [];
var clickStatus = false;
var labelEntity = null;
handler.setInputAction(function (clickEvent) {
clickStatus = true;
// var cartesian = viewer.scene.pickPosition(clickEvent.position);
var cartesian = viewer.scene.globe.pick(viewer.camera.getPickRay(clickEvent.position), viewer.scene);
console.log(cartesian);
if (positions.length == 0) {
positions.push(cartesian.clone()); //鼠标左击 添加第1个点
addPoint(cartesian);
handler.setInputAction(function (moveEvent) {
// var movePosition = viewer.scene.pickPosition(moveEvent.endPosition);
var movePosition = viewer.scene.globe.pick(viewer.camera.getPickRay(moveEvent.endPosition), viewer.scene);
console.log(movePosition);
if (positions.length == 1) {
positions.push(movePosition);
addLine(positions);
} else {
if (clickStatus) {
positions.push(movePosition);
} else {
positions.pop();
positions.push(movePosition);
}
}
if (positions.length >= 3) {
// 绘制label
if (labelEntity) {
viewer.entities.remove(labelEntity);
entityCollection.splice(entityCollection.indexOf(labelEntity), 1);
}
var text = "面积：" + getArea(positions);
var centerPoint = getCenterOfGravityPoint(positions);
labelEntity = addLabel(centerPoint, text);
entityCollection.push(labelEntity);
}
clickStatus = false;
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
} else if (positions.length == 2) {
positions.pop();
positions.push(cartesian.clone()); // 鼠标左击 添加第2个点
addPoint(cartesian);
addPolyGon(positions);
// 右击结束
handler.setInputAction(function (clickEvent) {
// var clickPosition = viewer.scene.pickPosition(clickEvent.position);
var clickPosition = viewer.scene.globe.pick(viewer.camera.getPickRay(clickEvent.position), viewer.scene);
console.log(clickPosition);
positions.pop();
positions.push(clickPosition);
positions.push(positions[0]); // 闭合
addPoint(clickPosition);
handler.removeInputAction(Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.removeInputAction(Cesium.ScreenSpaceEventType.MOUSE_MOVE);
handler.removeInputAction(Cesium.ScreenSpaceEventType.RIGHT_CLICK);
}, Cesium.ScreenSpaceEventType.RIGHT_CLICK);
} else if (positions.length >= 3) {
positions.pop();
positions.push(cartesian.clone()); // 鼠标左击 添加第3个点
addPoint(cartesian);
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
};
/**
* 测高
*/
this.measureHeight = function () {
var positions = [];
var labelEntity_1 = null; // 标签实体
var labelEntity_2 = null; // 标签实体
var labelEntity_3 = null; // 标签实体
// 注册鼠标左击事件
handler.setInputAction(function (clickEvent) {
var cartesian = viewer.scene.pickPosition(clickEvent.position); // 坐标
// 存储第一个点
if (positions.length == 0) {
positions.push(cartesian.clone());
addPoint(cartesian);
// 注册鼠标移动事件
handler.setInputAction(function (moveEvent) {
var movePosition = viewer.scene.pickPosition(moveEvent.endPosition); // 鼠标移动的点
if (positions.length >= 2) {
positions.pop();
positions.pop();
positions.pop();
var cartographic = Cesium.Cartographic.fromCartesian(movePosition);
var height = Cesium.Cartographic.fromCartesian(positions[0]).height;
var verticalPoint = Cesium.Cartesian3.fromDegrees(Cesium.Math.toDegrees(cartographic.longitude), Cesium.Math.toDegrees(cartographic.latitude), height);
positions.push(verticalPoint);
positions.push(movePosition);
positions.push(positions[0]);
// 绘制label
if (labelEntity_2) {
// viewer.entities.remove(labelEntity_1);
// entityCollection.splice(entityCollection.indexOf(labelEntity_1), 1);
viewer.entities.remove(labelEntity_2);
entityCollection.splice(entityCollection.indexOf(labelEntity_2), 1);
// viewer.entities.remove(labelEntity_3);
// entityCollection.splice(entityCollection.indexOf(labelEntity_3), 1);
}
// // 计算中点
// var centerPoint_1 = Cesium.Cartesian3.midpoint(positions[0], positions[1], new Cesium.Cartesian3());
// // 计算距离
// var lengthText_1 = "水平距离：" + getLengthText(positions[0], positions[1]);
// labelEntity_1 = addLabel(centerPoint_1, lengthText_1);
// entityCollection.push(labelEntity_1);
// 计算中点
var centerPoint_2 = Cesium.Cartesian3.midpoint(positions[1], positions[2], new Cesium.Cartesian3());
// 计算距离
var lengthText_2 = "垂直距离：" + getLengthText(positions[1], positions[2]);
labelEntity_2 = addLabel(centerPoint_2, lengthText_2);
entityCollection.push(labelEntity_2);
// // 计算中点
// var centerPoint_3 = Cesium.Cartesian3.midpoint(positions[2], positions[3], new Cesium.Cartesian3());
// // 计算距离
// var lengthText_3 = "直线距离：" + getLengthText(positions[2], positions[3]);
// labelEntity_3 = addLabel(centerPoint_3, lengthText_3);
// entityCollection.push(labelEntity_3);
} else {
var verticalPoint = new Cesium.Cartesian3(movePosition.x, movePosition.y, positions[0].z);
positions.push(verticalPoint);
positions.push(movePosition);
positions.push(positions[0]);
// 绘制线
addLine(positions);
}
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
} else {
// 存储第二个点
positions.pop();
positions.pop();
positions.pop();
var cartographic = Cesium.Cartographic.fromCartesian(cartesian);
var height = Cesium.Cartographic.fromCartesian(positions[0]).height;
var verticalPoint = Cesium.Cartesian3.fromDegrees(Cesium.Math.toDegrees(cartographic.longitude), Cesium.Math.toDegrees(cartographic.latitude), height);
positions.push(verticalPoint);
positions.push(cartesian);
positions.push(positions[0]);
addPoint(cartesian);
handler.removeInputAction(Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.removeInputAction(Cesium.ScreenSpaceEventType.MOUSE_MOVE);
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
};
/**
* 添加点
* @param position
*/
var addPoint = function (position) {
entityCollection.push(viewer.entities.add(new Cesium.Entity({
position: position,
point: {
color: Cesium.Color.GREEN,
pixelSize: 10,
scaleByDistance: new Cesium.NearFarScalar(500, 1.0, 2000, 0.0),
translucencyByDistance: new Cesium.NearFarScalar(500, 1.0, 2000, 0.0)
}
})));
};
/**
* 添加线
* @param positions
*/
var addLine = function (positions) {
var dynamicPositions = new Cesium.CallbackProperty(function () {
return positions;
}, false);
entityCollection.push(viewer.entities.add(new Cesium.Entity({
polyline: {
positions: dynamicPositions,
width: 4,
clampToGround:true,
material: Cesium.Color.RED
}
})));
};
/**
* 添加面
* @param positions
*/
var addPolyGon = function (positions) {
var dynamicPositions = new Cesium.CallbackProperty(function () {
return new Cesium.PolygonHierarchy(positions);
}, false);
entityCollection.push(viewer.entities.add(new Cesium.Entity({
polygon: {
hierarchy: dynamicPositions,
material: Cesium.Color.RED.withAlpha(0.6),
classificationType: Cesium.ClassificationType.BOTH // 贴地表和贴模型,如果设置了，这不能使用挤出高度
}
})));
};
/**
* 添加标签
* @param position
* @param text
*/
var addLabel = function (centerPoint, text) {
return viewer.entities.add(new Cesium.Entity({
position: centerPoint,
label: {
text: text,
font: '12pt sans-serif',
style: Cesium.LabelStyle.FILL_AND_OUTLINE, //FILL FILL_AND_OUTLINE OUTLINE
fillColor: Cesium.Color.YELLOW,
showBackground: true,//指定标签后面背景的可见性
backgroundColor: new Cesium.Color(0.165, 0.165, 0.165, 0.8), // 背景颜色
backgroundPadding: new Cesium.Cartesian2(6, 6),//指定以像素为单位的水平和垂直背景填充padding
pixelOffset: new Cesium.Cartesian2(0, -25)
}
}));
};
/**
* 计算两点距离
* @param firstPoint
* @param secondPoint
*/
var getLengthText = function (firstPoint, secondPoint) {
// 计算距离
var length = Cesium.Cartesian3.distance(firstPoint, secondPoint);
if (length > 1000) {
length = (length / 1000).toFixed(2) + " 公里";
} else {
length = length.toFixed(2) + " 米";
}
return length;
};
//计算多边形面积
var getArea = function (points) {
var radiansPerDegree = Math.PI / 180.0;//角度转化为弧度(rad)
var degreesPerRadian = 180.0 / Math.PI;//弧度转化为角度
/*角度*/
function Angle(p1, p2, p3) {
var bearing21 = Bearing(p2, p1);
var bearing23 = Bearing(p2, p3);
var angle = bearing21 - bearing23;
if (angle < 0) {
angle += 360;
}
return angle;
}
/*方向*/
function Bearing(from, to) {
from = Cesium.Cartographic.fromCartesian(from);
to = Cesium.Cartographic.fromCartesian(to);
var lat1 = from.latitude;
var lon1 = from.longitude;
var lat2 = to.latitude;
var lon2 = to.longitude;
var angle = -Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2));
if (angle < 0) {
angle += Math.PI * 2.0;
}
angle = angle * degreesPerRadian;//角度
return angle;
}
function distance(point1, point2) {
var point1cartographic = Cesium.Cartographic.fromCartesian(point1);
var point2cartographic = Cesium.Cartographic.fromCartesian(point2);
/**根据经纬度计算出距离**/
var geodesic = new Cesium.EllipsoidGeodesic();
geodesic.setEndPoints(point1cartographic, point2cartographic);
var s = geodesic.surfaceDistance;
//console.log(Math.sqrt(Math.pow(distance, 2) + Math.pow(endheight, 2)));
//返回两点之间的距离
s = Math.sqrt(Math.pow(s, 2) + Math.pow(point2cartographic.height - point1cartographic.height, 2));
return s;
}
var res = 0;
//拆分三角曲面
for (var i = 0; i < points.length - 2; i++) {
var j = (i + 1) % points.length;
var k = (i + 2) % points.length;
var totalAngle = Angle(points[i], points[j], points[k]);
var dis_temp1 = distance(points[j], points[0]);
var dis_temp2 = distance(points[k], points[0]);
res += dis_temp1 * dis_temp2 * Math.sin(totalAngle) / 2;
// console.log(res);
}
if (res < 1000000) {
res = Math.abs(res).toFixed(4) + " 平方米";
} else {
res = Math.abs((res / 1000000.0).toFixed(4)) + " 平方公里";
}
return res;
};
/**
* 计算多边形的中心（简单的处理）
* @param mPoints
* @returns {*[]}
*/
var getCenterOfGravityPoint = function (mPoints) {
var centerPoint = mPoints[0];
for (var i = 1; i < mPoints.length; i++) {
centerPoint = Cesium.Cartesian3.midpoint(centerPoint, mPoints[i], new Cesium.Cartesian3());
}
return centerPoint;
}
}
该博客详细介绍了如何使用Cesium库实现三维场景中的线段测量、面积测量和高度测量功能。通过监听鼠标点击和移动事件，动态绘制测量线、面和点，并实时显示测量结果。此外，还提供了清除测量数据的功能。
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